By design, the idleslope increments are restricted to 16.384kbps steps.
Add a comment to igb_main.c making that explicit and add one example
that illustrates the impact of that.
Signed-off-by: NJesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>